MECHANICAL PROPERTIES AND MICROSTRUCTURAL CHARACTERIZATION OF A MULTILAYERED MULTIPASS FRICTION STIR WELD IN STEEL

Conference · Tue Jan 01 00:00:00 EST 2013

OSTI ID:1076897

Lim, Yong Chae ^[1]; Sanderson, Samuel ^[2]; Mahoney, Murray ^[3]; Qiao, Dongxiao ^[1]; Wang, Yanli ^[1]; Zhang, Wei ^[1]; Feng, Zhili ^[1]

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1. ORNL
2. MegaStir Technologies LLC
3. Consultant

Multilayered multipass friction stir welding (MM-FSW) makes it possible to use FSW to fabricate thick-section structures. In this work, MM-FSW was demonstrated on a high strength low alloy steel; ASTM A572 Grade 50. Three steel plates with thicknesses of 0.18", 0.18", 0.24" respectively were stacked and friction stir welded together to form a 0.6" thick welded structure. The welded plate was sectioned into rectangular bars transverse to the weld direction for tensile testing to evaluate mechanical properties. Digital image correlation (DIC) was employed to map the local strain fields during tensile testing. The initial failure was found to occur simultaneously at the bottom and middle layers away from the weld zone. The top layer failed last in the base metal. The failure locations were consistent among different samples tested. Also, Charpy V-notch impact tests were conducted for weld metal, heat affected zone, and the base metal at each layer as a function of temperature. The weld microstructures were characterized using optical and electron microscopy and micro-hardness mapping.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1076897
• Resource Relation: Conference: TMS 2013, San Antonio, TX, USA, 20130303, 20130307
• Country of Publication: United States
• Language: English